When I try to click the edges to resize sometimes it closes it out and will not reselect without restarting MuseScore 3 beta. The mixer panel seems to always be too large for the screen. Can’t see the bottom of the Mixer panel.

The Mixer will not resize when I am at 150%. It seems to partially work if I keep my screen size at 125%. However for my eye sight this is too small to work with.Mixer Bug.docx

Same for me on Linux Mate. The Mixer is always too large so I can't see the bottom part of it (screen size 1920x1080). What is the minimal proposed screen size for using Musescore? The sliders probably are designed for touch screen usage. They should scale properly at normal screens.
BTW: Questions to Windows users: What do you mean with a zoom of 150% or 125%? Is it a setting in Musescore or a Windows setting? In Musescore I can only find the possibility to zoom the score and that does not change any layout of the GUI.

BTW: Forgotten to mention: IMHO in the new GUI there is a lot of waste screen estate in parts of the panels like Mixer, Play-Panel, ... and e.g. I can reduce the size of the icons in the Settings dialog but it does not reduce the size of the upper bar for the Zoom and Page View buttons stay big with a lot of empty space around the percentage number.

What do you mean with a zoom of 150% or 125%? Is it a setting in Musescore or a Windows setting It i a Windows/Screen setting(screen size 1920x1080). What is the minimal proposed screen size for using Musescore? That is enough, at 100%